Downhill Mountain Bikes

Downhill Mountain Bike Buyer’s Guide

Downhill bikes are made to go down hills, fast. These bikes are always full-suspension with 7 to 10-inches of suspension travel in the rear and 7 to 8-inches up front to absorb big impacts when landing drops or smashing through rock gardens. It's very rare to see a downhill bike without a chainguide, which prevent the chain from falling off the single front chainring while riding. They also come with wide, grippy tires and large diameter disc brakes to ensure riders have traction and stopping power when they need it. Because most downhill components and frames are built with durability in mind, these bikes usually weigh between 38 and 42 pounds.

Typical Downhill Mountain Bike

Things to Look for in an Downhill Mountain Bike

Suspension: The quality of fork and rear shock play a major role in how a bike rides. Look for suspension featuring rebound, compression, and preload settings.

Brakes: Brakes that perform well encourage you to ride better, simply because you know that when you need to stop or slow down, you can. Look for hydraulic disc brakes from a reputable brand (Avid, Hayes, Shimano, Magura, and Hope are all good brands). 8-inch diameter brake rotors are strongly recommended.

Chain Retention: True downhill bikes will have only one front chainring. With how much vibration and chatter you’ll experience while riding downhill, it’s crucial to ensure that there is a chainguide on the front sprocket.

Wheels: Wheels take a beating when downhilling. Because of this, look for wheels that have 36 spokes and always run at least 25 psi in your tires (some racers run less pressure, but wheels are at a greater risk when below 25 psi).

Tires: Wide tires are a necessity for downhill bikes because they offer more traction and flat protection. Look for tires ranging from 2.4 to 2.7-inches wide.

Downhill Mountain Bike Frame Sizes

The most common way to size a downhill bike is the horizontal distance between the center of the head tube and the center of the seat tube. This measure is called 'effective top tube length' and sometimes 'horizontal top tube length'. The taller you are, the longer the top tube you’ll want. In general, riders more than 5’11” tall ride large downhill frames.

Most manufacturers provide suggested sizing charts, and because models vary so much between categories, we recommend searching for the chart specific to the bike you’re interested in. It’s important to note that everyone has different riding preferences, so it’s best to test out a variety of sizes before making a final decision.

General Downhill MTB Size Chart

Bike Size

Small

Medium

Large

Extra Large

Rider Height

<5'8"

5'7"-6'

5'11"-6'4"

>6'3"

Downhill Mountain Bike Frame Materials

The overall feel of a bike is largely dependent on what material(s) the frame is made of, so this is an important consideration.

Aluminum - Aluminum is light, stiff, and affordable, making it the most commonly used frame material. Because it is so stiff, aluminum bikes are characterized by a slightly rougher ride than those made from chromoly or titanium.

Carbon Fiber - Carbon fiber is basically very thin strands of carbon that can be twisted and woven together, like cloth. To make carbon fiber take on a permanent shape, it can be layered over a mold, then coated with a stiff resin or plastic. It is among the lightest materials and is commonly used for high-end cross-country and all-mountain bikes. More recently it has found its way into some downhill and freeride frames. Because carbon technology is advancing very quickly, costs are being lowered and durability is increasing.

Chromoly Steel - Chromoly (a steel alloy) is lighter than high-tensile steel, strong, responsive, and offers a relatively supple ride. However, it is heaver than aluminum, carbon, and titanium.

Material Combinations - If a frame is made of more than one material, it is usually carbon fiber and a metal - either steel, aluminum, or titanium. Material blends are not common, but constructing various parts of a frame from different materials is (ie – a carbon fiber front triangle with an aluminum swingarm). A frame made out of more than one material can help provide better stiffness, compliance, or damping in specific areas.

How Much to Spend

Deciding how much to spend is a tough decision. As a general rule, the more you spend the better bike you get. There will be major difference between a $2000 bike and a $5500 bike. In general, the more expensive a bike is, the more durable it will be (at least until you start getting into the high-end where lightweight construction may reduce durability) and the better components will perform. If you’ll be riding regularly, we recommend spending at least $2000 on a downhill bike. Anything less and you’ll be constantly repairing the bike and replacing components. If you’re a first-time buyer, you may be tempted to purchase a low-end bike and later upgrade the components as necessary. Know that it is often much cheaper to buy the components on the bike in the first place than it is to buy components later and upgrade.

For comparison, the two bikes below are priced at $5600 and $9400, respectively.

Product Reviews

Be sure to do your research and read product reviews. Reviews are a great way to find out specifics about a particular model of mountain bike, user impressions, and things to watch out for or to upgrade right off the bat. After you’ve purchased a bike and had enough time to thoroughly test it, we encourage you to leave a review for other people to see when they are researching bikes on the web.

We hope you’ve found this information to be helpful. If you have a question that isn’t answered in this guide, our mountain bike forums are a great place to get advice from knowledgeable riders. Your local bike shop is also a great resource and the best place to test ride bikes before making a final decision.